Analysis of computational and experimental researches on systems for individual control of the blades of the helicopter

Аuthors

Animitsa V. A.^*, Borisov A. E.^*, Kritsky B. S.^**, Mirgazov R. M.^***

Central Aerohydrodynamic Institute named after N.E. Zhukovsky (TsAGI), 1, Zhukovsky str., Zhukovsky, Moscow Region, 140180, Russia

*e-mail: spintest@tsagi.ru
**e-mail: boris.kritsky@tsagi.ru
***e-mail: ruslan.mirgazov@tsagi

Abstract

The article gives a review of methods for individual blade control of the helicopter rotor. Low and high harmonics control features in order to improve aerodynamic performance, reducing vibro g-load and noise of the helicopter were presented.

It is established that one of the directions of works to increase in flight speed is individual blades control of the helicopter rotor, which is the implement for addition control of the blades attack angles, superimposed on standard controls from the collective and cyclic pitch control mechanism. Researches abroad for individual blades control is aimed to reducing vibro g-load and noise of the main rotor, to improve the aerodynamic characteristics of the carrier system and finding ways of rejecting traditional collective and cyclic pitch control mechanism.

Individual blades control of the helicopter rotor can be divided into two components: 1) low harmonics control (rotational frequencies and their overtones) and 2) high harmonics control (blade frequencies pass and their overtones). The purpose of the low harmonics control is to improve the aerodynamic characteristics of the rotor by reducing areas of stall on the retreating blades of the rotor and approach angle of attack sections of the blades for the optimum profile quality. The purpose of the high harmonics control is to reduce vibro g-load and noise of helicopter rotor on the flight modes with large horizontal velocity.

The article describes the different methods used to individual blades control of the helicopter rotor:

• The control of the high harmonics through the fixed plate swashplate.

• Individual blades control of MR driven by actuators built into the mechanism of movable rods swashplate.

• Use active flaps embedded on the trailing edge of the blade with integrated in its design actuators.

• Use blade with variable twist, actuators inside the blades or built into their hull or spar.

• Individual blades control of a rotor using two disk plate swashplate.

• Individual blades control by means of actuators, built-in axial hinges of the rotor hub.

The results of numerical investigation of the influence of individual blade control by azimuth by means of cyclic change of the angle of installation to reduce vibro g-load transmitted to the hub from helicopter main rotor.

The influence of the main (the fifth blade harmonic, for 5 blades rotor) harmonic was investigated. It is established that the selection of the amplitude and phase controls for separate blade is possible to minimize the amount of vibro g-load.

Keywords:

rotors of the helicopter, drive, harmonics, vibro g-load, individual control of the blades

References

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